diff options
Diffstat (limited to '')
-rw-r--r-- | tools/bpf/bpftool/xlated_dumper.c | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c new file mode 100644 index 000000000..13d614b16 --- /dev/null +++ b/tools/bpf/bpftool/xlated_dumper.c @@ -0,0 +1,380 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +/* Copyright (C) 2018 Netronome Systems, Inc. */ + +#define _GNU_SOURCE +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/types.h> +#include <bpf/libbpf.h> + +#include "disasm.h" +#include "json_writer.h" +#include "main.h" +#include "xlated_dumper.h" + +static int kernel_syms_cmp(const void *sym_a, const void *sym_b) +{ + return ((struct kernel_sym *)sym_a)->address - + ((struct kernel_sym *)sym_b)->address; +} + +void kernel_syms_load(struct dump_data *dd) +{ + struct kernel_sym *sym; + char buff[256]; + void *tmp, *address; + FILE *fp; + + fp = fopen("/proc/kallsyms", "r"); + if (!fp) + return; + + while (fgets(buff, sizeof(buff), fp)) { + tmp = reallocarray(dd->sym_mapping, dd->sym_count + 1, + sizeof(*dd->sym_mapping)); + if (!tmp) { +out: + free(dd->sym_mapping); + dd->sym_mapping = NULL; + fclose(fp); + return; + } + dd->sym_mapping = tmp; + sym = &dd->sym_mapping[dd->sym_count]; + if (sscanf(buff, "%p %*c %s", &address, sym->name) != 2) + continue; + sym->address = (unsigned long)address; + if (!strcmp(sym->name, "__bpf_call_base")) { + dd->address_call_base = sym->address; + /* sysctl kernel.kptr_restrict was set */ + if (!sym->address) + goto out; + } + if (sym->address) + dd->sym_count++; + } + + fclose(fp); + + qsort(dd->sym_mapping, dd->sym_count, + sizeof(*dd->sym_mapping), kernel_syms_cmp); +} + +void kernel_syms_destroy(struct dump_data *dd) +{ + free(dd->sym_mapping); +} + +struct kernel_sym *kernel_syms_search(struct dump_data *dd, + unsigned long key) +{ + struct kernel_sym sym = { + .address = key, + }; + + return dd->sym_mapping ? + bsearch(&sym, dd->sym_mapping, dd->sym_count, + sizeof(*dd->sym_mapping), kernel_syms_cmp) : NULL; +} + +static void __printf(2, 3) print_insn(void *private_data, const char *fmt, ...) +{ + va_list args; + + va_start(args, fmt); + vprintf(fmt, args); + va_end(args); +} + +static void __printf(2, 3) +print_insn_for_graph(void *private_data, const char *fmt, ...) +{ + char buf[64], *p; + va_list args; + + va_start(args, fmt); + vsnprintf(buf, sizeof(buf), fmt, args); + va_end(args); + + p = buf; + while (*p != '\0') { + if (*p == '\n') { + memmove(p + 3, p, strlen(buf) + 1 - (p - buf)); + /* Align each instruction dump row left. */ + *p++ = '\\'; + *p++ = 'l'; + /* Output multiline concatenation. */ + *p++ = '\\'; + } else if (*p == '<' || *p == '>' || *p == '|' || *p == '&') { + memmove(p + 1, p, strlen(buf) + 1 - (p - buf)); + /* Escape special character. */ + *p++ = '\\'; + } + + p++; + } + + printf("%s", buf); +} + +static void __printf(2, 3) +print_insn_json(void *private_data, const char *fmt, ...) +{ + unsigned int l = strlen(fmt); + char chomped_fmt[l]; + va_list args; + + va_start(args, fmt); + if (l > 0) { + strncpy(chomped_fmt, fmt, l - 1); + chomped_fmt[l - 1] = '\0'; + } + jsonw_vprintf_enquote(json_wtr, chomped_fmt, args); + va_end(args); +} + +static const char *print_call_pcrel(struct dump_data *dd, + struct kernel_sym *sym, + unsigned long address, + const struct bpf_insn *insn) +{ + if (!dd->nr_jited_ksyms) + /* Do not show address for interpreted programs */ + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "%+d", insn->off); + else if (sym) + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "%+d#%s", insn->off, sym->name); + else + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "%+d#0x%lx", insn->off, address); + return dd->scratch_buff; +} + +static const char *print_call_helper(struct dump_data *dd, + struct kernel_sym *sym, + unsigned long address) +{ + if (sym) + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "%s", sym->name); + else + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "0x%lx", address); + return dd->scratch_buff; +} + +static const char *print_call(void *private_data, + const struct bpf_insn *insn) +{ + struct dump_data *dd = private_data; + unsigned long address = dd->address_call_base + insn->imm; + struct kernel_sym *sym; + + if (insn->src_reg == BPF_PSEUDO_CALL && + (__u32) insn->imm < dd->nr_jited_ksyms && dd->jited_ksyms) + address = dd->jited_ksyms[insn->imm]; + + sym = kernel_syms_search(dd, address); + if (insn->src_reg == BPF_PSEUDO_CALL) + return print_call_pcrel(dd, sym, address, insn); + else + return print_call_helper(dd, sym, address); +} + +static const char *print_imm(void *private_data, + const struct bpf_insn *insn, + __u64 full_imm) +{ + struct dump_data *dd = private_data; + + if (insn->src_reg == BPF_PSEUDO_MAP_FD) + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "map[id:%u]", insn->imm); + else if (insn->src_reg == BPF_PSEUDO_MAP_VALUE) + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "map[id:%u][0]+%u", insn->imm, (insn + 1)->imm); + else + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "0x%llx", (unsigned long long)full_imm); + return dd->scratch_buff; +} + +void dump_xlated_json(struct dump_data *dd, void *buf, unsigned int len, + bool opcodes, bool linum) +{ + const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo; + const struct bpf_insn_cbs cbs = { + .cb_print = print_insn_json, + .cb_call = print_call, + .cb_imm = print_imm, + .private_data = dd, + }; + struct bpf_func_info *record; + struct bpf_insn *insn = buf; + struct btf *btf = dd->btf; + bool double_insn = false; + unsigned int nr_skip = 0; + char func_sig[1024]; + unsigned int i; + + jsonw_start_array(json_wtr); + record = dd->func_info; + for (i = 0; i < len / sizeof(*insn); i++) { + if (double_insn) { + double_insn = false; + continue; + } + double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW); + + jsonw_start_object(json_wtr); + + if (btf && record) { + if (record->insn_off == i) { + btf_dumper_type_only(btf, record->type_id, + func_sig, + sizeof(func_sig)); + if (func_sig[0] != '\0') { + jsonw_name(json_wtr, "proto"); + jsonw_string(json_wtr, func_sig); + } + record = (void *)record + dd->finfo_rec_size; + } + } + + if (prog_linfo) { + const struct bpf_line_info *linfo; + + linfo = bpf_prog_linfo__lfind(prog_linfo, i, nr_skip); + if (linfo) { + btf_dump_linfo_json(btf, linfo, linum); + nr_skip++; + } + } + + jsonw_name(json_wtr, "disasm"); + print_bpf_insn(&cbs, insn + i, true); + + if (opcodes) { + jsonw_name(json_wtr, "opcodes"); + jsonw_start_object(json_wtr); + + jsonw_name(json_wtr, "code"); + jsonw_printf(json_wtr, "\"0x%02hhx\"", insn[i].code); + + jsonw_name(json_wtr, "src_reg"); + jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].src_reg); + + jsonw_name(json_wtr, "dst_reg"); + jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].dst_reg); + + jsonw_name(json_wtr, "off"); + print_hex_data_json((uint8_t *)(&insn[i].off), 2); + + jsonw_name(json_wtr, "imm"); + if (double_insn && i < len - 1) + print_hex_data_json((uint8_t *)(&insn[i].imm), + 12); + else + print_hex_data_json((uint8_t *)(&insn[i].imm), + 4); + jsonw_end_object(json_wtr); + } + jsonw_end_object(json_wtr); + } + jsonw_end_array(json_wtr); +} + +void dump_xlated_plain(struct dump_data *dd, void *buf, unsigned int len, + bool opcodes, bool linum) +{ + const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo; + const struct bpf_insn_cbs cbs = { + .cb_print = print_insn, + .cb_call = print_call, + .cb_imm = print_imm, + .private_data = dd, + }; + struct bpf_func_info *record; + struct bpf_insn *insn = buf; + struct btf *btf = dd->btf; + unsigned int nr_skip = 0; + bool double_insn = false; + char func_sig[1024]; + unsigned int i; + + record = dd->func_info; + for (i = 0; i < len / sizeof(*insn); i++) { + if (double_insn) { + double_insn = false; + continue; + } + + if (btf && record) { + if (record->insn_off == i) { + btf_dumper_type_only(btf, record->type_id, + func_sig, + sizeof(func_sig)); + if (func_sig[0] != '\0') + printf("%s:\n", func_sig); + record = (void *)record + dd->finfo_rec_size; + } + } + + if (prog_linfo) { + const struct bpf_line_info *linfo; + + linfo = bpf_prog_linfo__lfind(prog_linfo, i, nr_skip); + if (linfo) { + btf_dump_linfo_plain(btf, linfo, "; ", + linum); + nr_skip++; + } + } + + double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW); + + printf("% 4d: ", i); + print_bpf_insn(&cbs, insn + i, true); + + if (opcodes) { + printf(" "); + fprint_hex(stdout, insn + i, 8, " "); + if (double_insn && i < len - 1) { + printf(" "); + fprint_hex(stdout, insn + i + 1, 8, " "); + } + printf("\n"); + } + } +} + +void dump_xlated_for_graph(struct dump_data *dd, void *buf_start, void *buf_end, + unsigned int start_idx) +{ + const struct bpf_insn_cbs cbs = { + .cb_print = print_insn_for_graph, + .cb_call = print_call, + .cb_imm = print_imm, + .private_data = dd, + }; + struct bpf_insn *insn_start = buf_start; + struct bpf_insn *insn_end = buf_end; + struct bpf_insn *cur = insn_start; + bool double_insn = false; + + for (; cur <= insn_end; cur++) { + if (double_insn) { + double_insn = false; + continue; + } + double_insn = cur->code == (BPF_LD | BPF_IMM | BPF_DW); + + printf("% 4d: ", (int)(cur - insn_start + start_idx)); + print_bpf_insn(&cbs, cur, true); + if (cur != insn_end) + printf(" | "); + } +} |